Help with GREP search

[#1]

I'm trying to make a plain text so, that I can batch process all the layout formatting in one go.

I'm using this now for the GREP search/replace:

(!CSNUM2!)(\w\s*.*)(!CSNUM2!)

Is there a way that I can add to this formula it would include a (hard) line break? For example, all text between !CSNUM2! needs to become Arial Narrow, 11pt:

!CSNUM2!This is a line.
This is a second line.

This is a third line.

And so on!CSNUM2!

I've tried this on a document, but it applies the search/replace only to single lines.
I've also tried to add the multiline on (?m), but that doesn't work. Adding a forced line break \n to the code doesn't work, neither does the standard carriage return ~b.

Having to put the !CSNUM2! before and after every single line is going to take so much time that I can just go through the whole text by hand.

Any pointers?

[#2]

Use single line modifier at the begining...

(?s)

[#3]

You might also want to try this one:

(!CSNUM2!)(\X+)(\1)

[#4]

Neither of these seem to work.
I don't know if it makes a difference to the response, but in the replace box I have $2 and a paragraph style set to change into.

[#5 · Accepted solution]

The 2nd term between parenthesis of your Grep code has to be:

\X+?

(^/)  The Jedi

[#6]

Lifesaver! Thank you so much!

[#7]

As so often, you can use different expressions for this. Apart from what Jean-Claude suggested (and Michel's correction) you can use a negative character class:

(?s)!CSNUM2!.+?!CSNUM2!
!CSNUM2!\X+?!CSNUM2!
!CSNUM2![^?]+?!CSNUM2!

P.